ARBUTUS, Md. - Mitt Romney sought to capitalize Wednesday on his sweeping victory in Illinois, hailing the surprise endorsement from one of his party’s beacons, Jeb Bush, while trying to corral support from other prominent Republicans.

Yet comments from a top aide inadvertently turned a morning of celebration into an afternoon of damage control for the GOP presidential candidate. Eric Fehrnstrom appeared to imply on CNN that Romney could essentially wipe away the arch conservative views he has forcefully espoused in the primaries once he pivots to take on President Obama in the general election.

“You hit a reset button for the fall campaign,’’ Fehrnstrom said in explaining why the campaign is not concerned about alienating moderates as Romney tacks to the right to attract primary conservatives. “Everything changes. It’s almost like an Etch A Sketch - you can kind of shake it up, and we start all over again.’’

The blowback from the comment was immediate. Rivals Rick Santorum and Newt Gingrich seized on the imagery to reiterate their contention Romney is a political chameleon, changing his views to fit the moment. The campaigns went to local stores to pick up the drawing toy and display it at rallies in Louisiana.

“If we’re dumb enough to nominate him, we should expect by the acceptance speech he’ll move back to the left,’’ Gingrich said. “Governor Romney’s staff doesn’t have the decency to wait until they get the nomination to explain to us how they’ll sell us out.’’

“We’re not looking for someone who is the Etch a Sketch candidate,’’ Santorum said. “We’re looking for someone who writes what they believe in in stone and stands true to what they say.’’

Wikipedia’s page for Etch A Sketch was updated with a photo of Romney at the top, and the company making the toy, Ohio Art, issued a statement saying it was pleased to be “shaking up the national debate.’’

Within hours, the Democratic National Committee had a Web ad out ridiculing Romney.

“We’ve been saying it for months, and Mitt Romney has had a reputation for it for years: He’ll say or do anything to get elected - absolutely anything,’’ Brad Woodhouse, the communications director for the DNC, said in an e-mail to reporters. The subject line was, “An Etch a Sketch? Really??’’

Romney throughout the campaign has been dogged by accusations he is merely a conservative of convenience. Tea Party activists and other critics have pointed to his political flexibility on several issues over the past two decades, including abortion and gun rights, and said that he cannot be trusted.

Romney’s campaign said later that Fehrnstrom was referring not to altering Romney’s positions but to campaign strategy.

As Romney was shaking hands following a town hall meeting here, he initially refused to answer questions about the matter, saying he was not doing a press conference. But several minutes later his aides called Romney back, and he agreed to answer a single question about the Etch A Sketch comment.

“The issues I’m running on will be exactly the same,’’ Romney said. “I’m running as a conservative Republican. I was a conservative Republican governor, and I’ll be running as a conservative Republican . . . nominee for president.’’

At the event, a Santorum spokeswoman had passed out Etch A Sketches, seeking a replay of how protesters wielded giant flip-flops to chide John Kerry over his position changes in 2004.

Fehrnstrom has been one of Romney’s most trusted and loyal aides, serving as his chief spokesman during his four-year term as Massachusetts governor and having prominent roles in his 2008 and 2012 presidential bids.

He is also a top campaign adviser to Republican Senator Scott Brown and has not been immune to controversy.

Last year, he set up a fake Twitter account to poke fun at Alan Khazei, who at the time was a potential Democratic opponent to Brown.

The fallout over the latest comments threatened to overshadow an endorsement from Bush, the former Florida governor, brother of former president George W. Bush, and son of former president George H.W. Bush, which had long been sought. A Romney aide said Bush called Romney about an hour before making the news public.

“Primary elections have been held in 34 states, and now is the time for Republicans to unite behind Governor Romney and take our message of fiscal conservatism and job creation to all voters this fall,’’ Bush said in a statement. “I am endorsing Mitt Romney for our party’s nomination.’’

Bush’s backing is considered crucial, not only because of his stature across the party’s spectrum but also because many Republicans had tried to cajole him into jumping in this year’s primaries.

While rejecting such requests, Bush has decried some of the harsh rhetoric in the race, particularly concerning illegal immigrants.

“I used to be a conservative, and I watch these debates and I’m wondering, I don’t think I’ve changed, but it’s a little troubling sometimes when people are appealing to people’s fears and emotion rather than trying to get them to look over the horizon for a broader perspective,’’ Bush said in Dallas last month. “And that’s kind of where we are.’’

Bush and his brother have long been proponents of reaching out to Hispanic Americans, a crucial and growing bloc of voters.

Romney has been eager to portray himself as the inevitable Republican nominee, in part by surrounding himself with elected officials who endorse his campaign. Romney is planning to meet with congressional members on Capitol Hill Thursday before traveling to Louisiana, which holds a primary Saturday.